linux-kernel - [tip: sched/core] sched/deadline: Add dl_bw

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <159231011211.16989.3507232109054333136.tip-bot2@tip-bot2>
Date:   Tue, 16 Jun 2020 12:21:52 -0000
From:   "tip-bot2 for Dietmar Eggemann" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Dietmar Eggemann <dietmar.eggemann@....com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>, x86 <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [tip: sched/core] sched/deadline: Add dl_bw_capacity()

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     fc9dc698472aa460a8b3b036d9b1d0b751f12f58
Gitweb:        https://git.kernel.org/tip/fc9dc698472aa460a8b3b036d9b1d0b751f12f58
Author:        Dietmar Eggemann <dietmar.eggemann@....com>
AuthorDate:    Wed, 20 May 2020 15:42:40 +02:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Mon, 15 Jun 2020 14:10:05 +02:00

sched/deadline: Add dl_bw_capacity()

Capacity-aware SCHED_DEADLINE Admission Control (AC) needs root domain
(rd) CPU capacity sum.

Introduce dl_bw_capacity() which for a symmetric rd w/ a CPU capacity
of SCHED_CAPACITY_SCALE simply relies on dl_bw_cpus() to return #CPUs
multiplied by SCHED_CAPACITY_SCALE.

For an asymmetric rd or a CPU capacity < SCHED_CAPACITY_SCALE it
computes the CPU capacity sum over rd span and cpu_active_mask.

A 'XXX Fix:' comment was added to highlight that if 'rq->rd ==
def_root_domain' AC should be performed against the capacity of the
CPU the task is running on rather the rd CPU capacity sum. This
issue already exists w/o capacity awareness.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@....com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Acked-by: Juri Lelli <juri.lelli@...hat.com>
Link: https://lkml.kernel.org/r/20200520134243.19352-3-dietmar.eggemann@arm.com
---
 kernel/sched/deadline.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index ec90265..01f474a 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -69,6 +69,34 @@ static inline int dl_bw_cpus(int i)
 
 	return cpus;
 }
+
+static inline unsigned long __dl_bw_capacity(int i)
+{
+	struct root_domain *rd = cpu_rq(i)->rd;
+	unsigned long cap = 0;
+
+	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
+			 "sched RCU must be held");
+
+	for_each_cpu_and(i, rd->span, cpu_active_mask)
+		cap += capacity_orig_of(i);
+
+	return cap;
+}
+
+/*
+ * XXX Fix: If 'rq->rd == def_root_domain' perform AC against capacity
+ * of the CPU the task is running on rather rd's \Sum CPU capacity.
+ */
+static inline unsigned long dl_bw_capacity(int i)
+{
+	if (!static_branch_unlikely(&sched_asym_cpucapacity) &&
+	    capacity_orig_of(i) == SCHED_CAPACITY_SCALE) {
+		return dl_bw_cpus(i) << SCHED_CAPACITY_SHIFT;
+	} else {
+		return __dl_bw_capacity(i);
+	}
+}
 #else
 static inline struct dl_bw *dl_bw_of(int i)
 {
@@ -79,6 +107,11 @@ static inline int dl_bw_cpus(int i)
 {
 	return 1;
 }
+
+static inline unsigned long dl_bw_capacity(int i)
+{
+	return SCHED_CAPACITY_SCALE;
+}
 #endif
 
 static inline